The present invention relates to an apparatus for distributing light, or optical energy, which propagates through an elongate light conducting element on a time-sharing basis, or alternately, to desired locations.
Various attempts have been made to implement lighting and other purposes by converging solar energy or artificial optical energy into a light conducting element through a lens or the like so that the converged energy may propagate therethrough to a desired location. The optical energy transmitted by the light conducting element may serve as a light source for photosynthetic reactions of, for example, chlorella or for forcing culture of tomato or the like, as has also been proposed in various forms.
Concerning cultivation of chlorella or like substance, a single photosynthetic reaction requires light only for about 100 microseconds and does not require it for the remaining 10 milliseconds or so, that is, the reaction proceeding for the latter period is a dark reaction (thermochemical reaction) which does not need any light. For the period of 10 milliseconds, photosynthesis proceeds more effectively when light is not supplied than when it is supplied. Also, intermittent supply of optical energy is rather favorable for ordinary plants in promoting effective transfer of the photosynthetic substances within the plants. Such advantages attainable with intermittent supply of optical energy energy are disclosed in my Japanese patent application Nos. 57-17238 and 57-224150 which corresponds to Kokai Nos. 85926 and 125822/84, respectively, for example. It is also known that even the human eyes do not need continuous supply of optical energy because they retain an afterimage for a certain period of time after the cutoff of light supply.
It will be understood from the above that desired effects are sufficiently achievable if the supply of optical energy is not continuous, and continuous supply of light is rather undesirable for some applications. It is almost impossible, however, to attain a light source capable of building up and falling quick enough for the supply of optical energy whose intervals are quite short; if not impossible, such a light source would bring about various problems from the standpoint of costs, service life, etc.
Meanwhile, where optical energy is to be repeatedly turned on and off with predetermined intervals and a wide area or a plurality of locations are to be illuminated, a plurality of light sources have to be employed in a general sense and turned on and off individually. This would result in a significant number of light sources and, therefore, prohibitive costs and maintenance work.